The present invention relates to a gas control device for use with a container of compressed gas, and to a method of supplying gas from such a container.
The term gas encompasses both a permanent gas and a vapor of a liquefied gas. Permanent gases are gases which cannot be liquefied by pressure alone, and for example can be supplied in cylinders at pressures up to 300 bar g. Examples are argon and nitrogen. Vapors of liquefied gases are present above the liquid in a compressed gas cylinder. Gases which liquefy under pressure as they are compressed for filling into a cylinder are not permanent gases and are more accurately described as liquefied gases under pressure or as vapors of liquefied gases. As an example, nitrous oxide is supplied in a cylinder in liquid form, with an equilibrium vapor pressure of 44.4 bar g at 15xc2x0 C. Such vapors are not permanent or true gases as they are liquefiable by pressure or temperature around ambient conditions.
The conventional approach to handling gas from high pressure cylinders is to use a number of discrete components fitted to the outside of the cylinder to control such functions as pressure, flow, gas shut-off, and safety relief. Such arrangements are complex and bring problems of leaks, dead space, and numerous joints, giving difficulty in product quality and purity. Often the assembly must be enclosed in a gas cabinet which may need to be large and therefore expensive.
Compressed gas cylinders are used in a wide range of markets. In the low cost general industrial market, current standard cylinder valves are very cheap, but there is a requirement for additional functions to be built into the valve to give customers added benefits, such as direct pressure control and flow control in medical applications. In the higher cost end, such as electronics, there is a need to eliminate the problems associated with corrosion, contamination, and human exposure when making and breaking connections to the gas container, when using high purity corrosive, toxic and pyrophoric electronic speciality gases.
An example of these difficulties arises in the refilling procedure for a gas cylinder. Normally cylinders contain high pressure gases which are usually controlled by a simple shut-off cylinder valve (with a built-in rupture disc in the USA). Usually the gas will be used at a pressure substantially lower than that in the container, and the user will connect in the circuit a pressure reducing means such as an expansion valve. When there is a need to refill the gas cylinder, the shut-off valve on the cylinder is closed and the high pressure circuit is disconnected. This make and break at the high pressure of the cylinder gives the possibility of leakage and contamination. Attempts have been made to overcome this by refilling without making the high pressure disconnection.
In EP-A-0 275 242 (AGA AKTIEBOLAG) published on Jul. 20th 1988, there is disclosed an integrated cylinder valve control device intended for use primarily in gas therapy and intended to be permanently connected to a gas cylinder and surrounded by a protective cup fixedly mounted to the cylinder. The valve has a valve housing with a connection socket for the gas cylinder, and a residual gas valve and a non-return valve. The control device further includes a regulator disposed in the valve housing and operative to reduce the cylinder pressure to suitable working pressure, a shut-off valve for the gas, a quick coupling device for connection of a consumption conduit, a device for connection of a gas replenishment conduit to the cylinder, and a device for indicating the gas content in the cylinder.
In EP-A-0308875 (Union Carbide Corporation) published on Mar. 29th 1989 there is disclosed a valve-regulator assembly for rendering a high pressure gas source compatible with lower pressure equipment, the valve regulator being sealable or remote from the high pressure, gas source enabling recharging at high pressure. In one embodiment, a single outlet is used for a low pressure outlet, after pressure has been reduced by a regulator, and the same outlet is used with an adaptor to recharge the cylinder. When the adaptor is used, closure means on the adaptor plug moves the regulator to a fixed position sealing off gas flow from the main conduit without regard to the gas pressure otherwise acting on the regulator. Recharging of the cylinder then takes place through the adaptor. This enables complete shut-off of high pressure gas before recharging, so as to avoid make and break at high pressure.
A similar device is disclosed in U.S. Pat. No. 5,033,499 (Patel et al) published on Jul. 23rd 1991. A pressure reducing valve is mounted directly on a high pressure gas cylinder. When a standard adaptor is inserted in the outlet and a control handwheel is opened, gas is available at the outlet at a required low pressure, for example a maximum pressure of 200 bar. When a special filling adaptor is inserted in the outlet, the cylinder can be refilled to its maximum pressure of 300 bar. The special filling adaptor has a seal which inhibits gas flow from a chamber in the valve assembly via a passage in the assembly to the surrounding atmosphere. This in turn inhibits a piston moving downwardly to close the inlet of the pressure reducing valve as would be the case in normal service.
However these prior disclosures provide only limited function in the body of the assembly, namely normal low pressure regulation by manual control, and/or the ability to refill. Further functions required by the user are provided by discrete components joined in the usual way to the low pressure outlet.
Attempts have been made to provide for a number of different functions to be carried out by components mounted directly on the head of a compressed gas cylinder. In U.S. Pat. No. 5,086,807 (Lasnier et al/L""Air Liquide) published on Feb. 11th 1992, there is disclosed a pressure reducer comprising a pressure reducer body including oppositely disposed bores for mounting inlet and outlet connecting devices, and the outer end of another bore defining a high pressure chamber in which the regulating valve is mounted. The pressure reducer body is adapted to receive a connecting device for a high pressure manometer defining a rest for a spring of a regulating valve which includes an annular truncated lining in which is force fittingly engaged a connecting rod between the regulating valve and the piston bounding the low pressure chamber. The invention proposes an industrial type pressure reducer of a simplified design, including a high pressure manometer and a low pressure manometer.
In U.S. Pat. No. 5,127,436 (Campion et al/L""Air Liquide) published on Jul. 7th 1992, there is disclosed a gas distribution adaptor and pressure reducer device for a high pressure gas cylinder. The device comprises an assembly intended to be mounted on a closure valve of the high pressure gas cylinder and comprises a manual control device operating a distribution valve in which the upstream end communicates with the closure valve, a pressure reducer and a safety device against over pressures between the distribution valve and an outlet for connection to a user circuit, as well as a manometer which measures the pressure upstream of the distribution valve.
However, yet again the number of functions provided in these devices mounted on the cylinder head is limited, and further functionality required is provided by conventional components connected to the outlet of the cylinder head control device.
In U.S. Pat. No. 5,163,475 (Gregoire/Praxair Technology, Inc.) published on Nov. 17th 1992 there is disclosed a micro panel for the delivery of gas from a supply cylinder to a tool location comprising an arrangement of valves, pressure regulator and associated components adapted to enhance the purity of the delivered gas and the safety of the gas delivery panel. The object of the invention is to provide a reduced size micro panel adapted for the control of ultra high purity hazardous gases. The panel components are arranged and ported so that the gas flow path is preferably straight flow-through, with minimum bends and stagnant gas pockets. The micro panel components are arranged such that the gas passage parts therein are aligned essentially in the same plane. A single or unitary block of metal e.g. stainless steel, can be machined to provide fluid passage ports for the interconnection of the valves and pressure regulator components. However although the micro panel is reduced in size, it retains the complexity of a normal size gas panel, and contains numerous connections between discrete components. Also, the functions provided by the panel are limited in number, and when further functions are required these are provided by additional conventional components. Furthermore, when it is desired to refill the compressed gas cylinder, a conventional make and break is made in the high pressure part of the circuit, to remove the cylinder for refilling.
In an article entitled xe2x80x9cA Revolutionary Actuator For Microstructuresxe2x80x9d in SENSORS, February 1993 by Helmers Publishing, Inc., describing products of Redwood MicroSystems, Inc. a solid state pressure regulator is described consisting of a micromachined pressure sensor and an electronic feedback loop, combined with a thermopneumatic actuator known by the trade mark xe2x80x9cFluistorxe2x80x9d. A cavity is etched in the silicon substrate and filled with a control liquid. When this liquid is heated, the silicon diaphragm flexes outward over the valve seat. The silicon diaphragm flexes outward to meet a second wafer bonded to the underside, which contains precise channels and holes designed to direct the flow of fluid to be controlled. The microvalve can be combined with a micromachined pressure or flow sensor and electronic feedback circuitry to create a small, accurate, and cost effective closed-loop control system. The valve can be used for proportional control of gas flow rates from microlitres per minute to litres per minute. Integrating the microvalve with a pressure sensor or a flow sensor and electronic feedback circuitry provides a closed loop, programmable pressure regulator or flow regulator. Because the regulator can be controlled by digital or analogue signals, pressure and flow can be controlled using a personal computer, or an existing control system. Such components find particular use in embodiments of the present invention.
In U.S. Pat. No. 5,409,526 (Zheng et al/Air Products and Chemicals, Inc.) published on Apr. 25th 1995, apparatus for supplying high purity gas comprises a cylinder having a valve with two internal ports. One internal port is used to fill the cylinder while the other is fitted with a purifier unit which removes particulates and impurities from the gas as it leaves the cylinder. The purified gas leaves the cylinder via the valve and after passing through a regulator, a flow control device and various lengths of tubing, all external to the apparatus and the cylinder, the gas passes through a conventional purifier to the point of use. The internal purifier reduces the load on the external purifier and decreases the frequency at which the purifier has to be recharged. The provision of two internal ports and internal valving allows provision for filling the container without the filling gas passing through the internal filter unit. However the pressure regulator is external to the cylinder head unit, so that changing the cylinder for refilling involves a conventional make and break at high pressure, upstream of the pressure reduction produced by the pressure regulator. Also, functional components such as the pressure regulator are connected by conventional means to the cylinder head unit, and are not mounted on the cylinder. This disclosure is an example of a cylinder mounted control device in which additional functionality, transparent to the user, is included in the cylinder package. The purifier and filtration media were added as cartridges to the cylinder valve. To maintain the integrity of the cylinder contents a residual pressure valve was included on the outlet port of the cylinder valve. The residual pressure valve prevents the cylinder from being contaminated by atmospheric contamination or contaminated from foreign gases by the user. To fill the cylinder and retain the integrity of the purifier and cylinder package the second internal port is provided, and contains an additional isolation valve for cylinder fills.
In U.S. Pat. No. 5,440,477 (Rohrberg et al/Creative Pathways, Inc.) published on Aug. 8th 1995, there is disclosed a miniature gas management system comprising a complete gas manifold that includes computer-controlled valves, actuators, regulators and transducers. The entire system resides within a housing that sits on the top of a conventional gas cylinder that would normally be enclosed within a gas cabinet. Outside the housing, an upper control panel contains an LCD display and a lower control panel holds a key pad control, a removable data pack, LED indicator lights, and an emergency shut-off switch. Inside the housing, a neck protrudes upwardly from the gas cylinder and provides a connection for a supply of gas within it to the gas manifold. The gas manifold is an assembly of valves, actuators, pressure regulators, welded fittings and transducers. The top of the housing is fitted with a process gas outlet offset from the axis of the gas cylinder, a vent connection and a purge-gas inlet. The apparatus seeks to reduce size by having component-to-components welds, to reduce the number of mechanical connections.
Although the disclosure provides a concept of a miniaturized gas panel mounted on the cylinder, the system is still intended to make and break the connection between the cylinder and the gas panel at the full pressure of the gas cylinder, when refilling the cylinder. The concept is that the entire miniaturized gas panel is removed from the cylinder when a new cylinder is installed, and the old cylinder is refilled. Thus the make and break continue to be made at the relatively high pressure of the cylinder. Furthermore, although the number of functional components provided in the miniature gas panel is greater than are conventionally mounted on the gas cylinder, the required combination is set for the gas panel, or is made to order by conventional connections and welding. If additional functionality is required, this can only be provided by joining further discrete components in conventional manner.
In FR-A-2 735 209 (L""Air Liquide) published on Dec. 13th 1996 there is disclosed a gas control device for use with a compressed gas cylinder, having a supporting body with a main gas flow path through the body, the supporting body having input connecting means for mounting the body on the compressed gas cylinder and connecting the gas flow path to communicate with the gas cylinder. The supporting body has formed within it an expansion valve providing pressure reducing means for providing gas in the flow path at a selected pressure substantially lower than that in the container, and a high pressure shut-off valve in the main gas flow path upstream of the pressure reducing means. Output connecting means are provided downstream of the pressure reducing means for connecting the main gas flow path to subsequent apparatus for utilizing the gas. The supporting body of the gas control device has filling means for filling the container with compressed gas through the input connecting means, by way of a passageway separate from the passageway through which the main gas flow path communicates with the pressurized gas cylinder. A high pressure gauge is provided upstream of the pressure reducing means, to provide an indication of the pressure in the compressed gas cylinder, and a low pressure gauge is provided downstream of the pressure reducing means. The expansion valve shown is located in a shaped cover forming a cylinder handling cap by which the gas cylinder can be maneuvered in use. Preferably the valve assembly is entirely located within the cap, which has access apertures for the various assembly inlets and outlets.
Although the gas control device disclosed provides additional functions in a single body mounted on top of the gas cylinder, which had not previously been provided in combination, the functions provided are limited to a high pressure shut-off valve, pressure reducing means, and high and low pressure gauges, and filling of the gas container by a separate inlet pathway while the gas control device is mounted on the gas container. Any other functions required by the user are provided by conventional components attached in series to the outlet connection of the gas control device, by way of discrete components in the normal way. The outlet of the main gas flow through the control device is generally perpendicular to the direction of the main gas flow through the body, and the threaded output connection is of conventional form for connection to further conventional components. Thus in summary, the functions provided by the device are limited, and the arrangements for adding further components are conventional by adding discrete components by normal junctions. Additional functions which may be required by the user of the compressed gas cylinder, for example purging functions, must be carried out by conventional components, separately connected to the various ports of the control device. There remains a need to provide a system which will give additional functions in a compact space, with flexibility to meet different requirements of different users of compressed gas containers.
In an article entitled xe2x80x9cBenefits Of A Minimalist Gas System Designxe2x80x9d by Phillips and Sheriff, in Solid State Technology, October 1996, there is described the design and construction of a fabrication plant for electronic equipment, including a gas control system. The main novel feature was that the pressure in the distribution system for each process gas was controlled by a single regulator at the gas source. This was in contrast to conventional arrangements in which separate local pressure regulation is usually installed for every process chamber gas loop to prevent interactions between multiple gas systems. The present invention finds application in gas control for fabrication systems such as described in the cited article.
In an article entitled xe2x80x9cThe Next Step In Process Gas Delivery: A Fully Integrated Systemxe2x80x9d by Cestari, Laureta and Itafugi, in Semiconductor International, January 1997 there is described an integrated gas delivery system intended to reduce internal volumes and eliminate entrapment areas to reduce contamination, for use in semiconductor fabrication processes. The article describes the need for integration in the gas control system by configuring a standard set of modular components into a system to meet any gas delivery process requirements. Components must be designed to connect to each other directly or to a common manifold without the use of fittings or welding. Component modularity and interchangeability requires a standard form factor for valves, regulators, transducers, filters, mass flow controllers and other components. The advantage of interchangeable modular components is said to be that, irrespective of the specific function of the component within an integrated gas system, it connects in the same way and fits in the same space. The advantage is mentioned of purging a gas control system without the need to disconnect the gas line from the gas cylinder. The need is explained to eliminate the conventional convoluted gas flow path and large volume in the gas delivery system by an improved flow path. However, the systems described in the article continue to use discrete components and merely are concerned with the miniaturization of connections between discrete components.
U.S. Pat. No. 5,566,713 (Lhomer et al), published Oct. 22nd 1996, relates to a gas control and dispensing assembly, intended to be connected to a tank containing the said gas under a high pressure, comprising a low-pressure outlet and, in series between the tank and the low-pressure outlet, a shut-off valve exposed to the high pressure, a pressure reducer means coupled to the shut-off valve and a flow regulator means. The object is said to be to provide a control and dispensing assembly which is in a compact and ergonomic unit form, typically permanently mounted on the as tank or bottle and providing all the functional and safety features required, both for dispensing gas and for filling the tank. The gas control and dispensing assembly comprises a lower block mounted on a gas bottle and comprising a manometer and a filling connector, and on which a subassembly is permanently mounted, axially movable in response to rotation of a tubular control and actuation member surrounding the subassembly, which contains a pressure reducer and an indexable flow regulator and has a low-pressure outlet and a medium-pressure outlet.
EP-A-0 588 531 (Kabushiki Kaisha Neriki) published Mar. 23rd 1994, relates to a valve assembly adapted to be attached to a gas cylinder containing a compressed gas and a liquefied gas for use in discharging out and charging the gas. A gas inlet, a stop valve, a pressure reducing valve and a gas outlet are arranged in series within a valve casing. The gas outlet and an outlet of said stop valve communicate with each other by a gas charging passage provided with a check valve. The gas outlet communicates with a secondary safety valve by a gas inducting passage. When a gas cylinder is charged with a gas, a gas charging mouthpiece is attached to the gas outlet. Thereupon, an opening or closing portion provided in the gas inducting passage is closed by an actuating portion provided in the mouthpiece. Thereby high pressure gas is not released from the secondary safety valve.
EP-A-0 459 966 (GCE Gas Control Equipment AB), published Dec. 4th 1991, relates to an arrangement in a gas regulator intended to be connected to a gas holder, to permit using the regulator also as shut-off and filling valve for the gas holder. The regulator is of the concurrent type and contains a differential pressure piston having different cross-sectional areas on the upper and the lower part thereof, which parts are sealed with respect to the regulator housing. Between the upper part of the piston and the regulator housing is provided a spring tending to move the piston away from the valve seat. The piston is manually displaceable towards the valve seat by means of an operating member acting on the upper part of the piston. The regulator also comprises a safety valve.
According to the present invention in a first aspect there is provided a modular gas control device for use with a container of compressed gas comprising a primary module, and a secondary module mounted on the primary module, the primary module comprising a first supporting body having a first main gas flow path through the body, the supporting body having input connecting means for mounting the body on a container of compressed gas and connecting the gas flow path to communicate with the gas container, pressure reducing means for providing gas in the flow path at a selected pressure substantially lower than that in the container, output connecting means downstream of the pressure reducing means for providing an outlet from the main gas flow path, a high pressure shut-off valve in the gas flow path upstream of the pressure reducing means, filling means for filling the container with compressed gas through the input connecting means, and a purge-gas inlet valve upstream of the pressure reducing means for admitting purge-gas to the main gas flow, said secondary module comprising a second supporting body having a second main gas flow path through the body, the second supporting body having second input connecting means for mounting the body on the primary module and connecting the second main gas flow path to the output connecting means of the primary module, and second output connecting means for providing an outlet from the second main gas flow path, the supporting body of the secondary module having a combination of at least two functional components for carrying out functions relating to gas flow.
Preferably the said at least two functional components comprise means for measuring and/or varying parameters of gas flow in the second supporting body, and/or for switching and/or venting and/or mixing gas flow in the second supporting body.
Preferably each supporting body of each module is a single body of material on or in which the functional components are mounted. However in some arrangements the supporting body may comprise two or more subsidiary bodies secured together to produce the supporting body on or in which the components are mounted. In some arrangements the supporting body may be metal with openings drilled or otherwise formed in the metal to receive functional components such as valves. In other arrangements however the device may be constructed in accordance with micro electromechanical systems (MEMS) technology, for example using a thermopneumatic microvalve formed in a body of silicon. Conveniently the same silicon body may then be used to provide a substrate for electronic printed circuits defining appropriate electronic control circuits for controlling the valve.
It is particularly preferred that the first supporting body of each module is structurally supported on the container solely by the input connecting means, for example by a conventional threaded boss entering into the conventional threaded opening of the top of a compressed gas cylinder. Preferably each module includes a housing surrounding the supporting body and spaced therefrom, the housing being shaped to provide means for handling the gas container. Conveniently openings may be made in the housing to give access to ports and components of the supporting body, and conveniently resilient material may be provided in the spacing between the supporting body and the housing.
It is particularly preferred that for each module the main gas flow path through the module is generally aligned for at least part (preferably at least the majority) of its length along a principal axis of the supporting body, which principal axis extends through the input connecting means and the output connecting means of the module, the principal axes of the two modules being coaxial. Where the gas container is a conventional gas cylinder, it is preferred that the gas control device is mounted on the gas container with the principal axes of the modules coaxial with the axis of the cylinder.
In some arrangements, the first supporting body also may have a high-pressure indicator upstream of the pressure-reducing means for indicating the pressure in the container, and a safety relief device comprising a rupture disc or a relief valve.
Preferably the first input connecting means comprises first and second flow paths; the first flow path leading from the container to the main gas flow path through the first supporting body, and the second flow path leading from the container to the said filling means. In such a case, there may be provided purifying means positioned within the gas container, interposed between the first flow path and the interior of the container for purifying gas leaving the container and passing into the said first main flow path.
In general in the various aspects of the invention, where the device includes purifying means, this can conveniently comprise a unit containing a substance selected from the group consisting of adsorbents, absorbents and mixtures thereof, whereby impurities are removed from the gas as it is withdrawn from the container thorough the unit. The unit may conveniently be as described in U.S. Pat. No. 5,409,526 (Zheng et al) the contents of which are incorporated herein by reference.
Preferably the primary module will include components giving further functions, and in a preferred example the first supporting body also has in the first main gas flow path upstream of the pressure reducing means, a high-pressure safety relief device, or a high-pressure safety-relief region adapted to provide structure for mounting of a safety relief device; and/or downstream of the pressure reducing means, a low pressure indicator, or a low-pressure indicator region adapted to provide structure for a pressure indicator for indicating the pressure in the main gas flow path downstream of the pressure reducing means. Preferably the first supporting body also has a high-pressure indicator upstream of the pressure-reducing means for indicating the pressure in the container. The said safety relief device may be a rupture disc, or a relief valve. The said structure provided for mounting a functional component may comprise a shaped portion of the first supporting body adapted to be drilled out during manufacture of the gas control device when the functional component is required in the finished product.
It will be appreciated that the invention extends to the provision of a gas control device in which certain functional components are not always provided, dependent upon the customer requirement. However, for flexibility and ease of manufacture, the invention encompasses structures in which provision is made for supplying the further functional components, if and when required. By way of example, the said structure provided for mounting a functional component may comprise a shaped portion of the first supporting body adapted to be drilled out during manufacture of the gas control device when the functional component is required in the finished product.
The secondary module may be selected by customer requirement from one of a number of compatible secondary modules. In one example the secondary module is a vacuum module comprising a vent port and switchable valve means for connecting the second input and output connecting means in a flow-path such that gas from the compressed gas cylinder vents through the vent port, and produces a vacuum at the output connecting means for evacuating further apparatus connectable to the output connecting means of the secondary module, the valve means being switchable to selectively direct gas flow from the input connecting means of the secondary module to either the vent means or the output connecting means. In another example, the secondary module is a purge module having switchable valve means for admitting purge-gas through a purge-gas inlet and directing the purge-gas through the module, out through an outlet connecting means and thence to purge a use apparatus. In a further example the secondary module is a mixer module having controllable valve means for adding to the gas flow through the main gas flow path of the secondary module a further gas so as to supply a mixture of gases at the output connecting means, and in one example the secondary module may include a source of the said further gas. In another example, the secondary module may include a further input means adapted to be connected to a source of said further gas external to the secondary module.
In accordance with a second aspect of the present invention, there is provided a modular gas control device for use with a container of compressed gas comprising a primary module, and a secondary module mounted on the primary module, the primary module comprising a first supporting body having a first main gas flow path through the body, the supporting body having input connecting means for mounting the body on a container of compressed gas and connecting the gas flow path to communicate with the gas container, pressure reducing means for providing gas in the flow path at a selected pressure substantially lower than that in the container, output connecting means downstream of the pressure reducing means for providing an outlet from the main gas flow path, a high pressure shut-off valve in the gas flow path upstream of the pressure reducing means, and filling means for filling the container with compressed gas through the input connecting means, said secondary module comprising a second supporting body having a second main gas flow path through the body, the second supporting body having second input connecting means for mounting the body on the primary module and connecting the second main gas flow path to the output connecting means of the primary module, and second output connecting means for providing an outlet from the second main gas flow path, the supporting body of the secondary module having a combination of two or more functional components for carrying out functions relating to gas flow, the gas container comprising a cylinder having a main cylinder axis, and each module having a principal axis passing through its input connecting means and its output connecting means, the main flow path of each module being aligned along its principal axis for at least part of the length thereof, and the principal axis of each module being substantially coaxial with the main cylinder axis.
The device may include at least two secondary modules, the first mentioned secondary module being mounted on the primary module, and the or each further secondary module being mounted to form a stack of secondary modules one above the other.
Preferred and optional features which have been set out with regard to previous and subsequent aspects of the invention, may also be provided in accordance with this aspect of the invention.
In accordance with a third main aspect of the present invention, there is provided a set of modules for providing a modular gas control device for use with a container of compressed gas, the set of modules comprising a primary module, and a plurality of secondary modules each adapted to be mounted on the primary module or on a further secondary module, the primary module comprising a first supporting body having a first main gas flow path through the body, the supporting body having input connecting means for mounting the body on a container of compressed gas and connecting the gas flow path to communicate with the gas container, pressure reducing means for providing gas in the flow path at a selected pressure substantially lower than that in the container, output connecting means downstream of the pressure reducing means for providing an outlet from the main gas flow path, and filling means for filling the container with compressed gas through the input connecting means, each secondary module comprising a second supporting body having a second main gas flow path through the body, the second supporting body having second input connecting means for mounting the body on the primary module or on a further secondary module and connecting the second main gas flow path to the main gas flow path of the primary module or the further secondary module, and second output connecting means for providing an outlet from the second main gas flow path, the supporting body of each secondary module having a combination of two or more functional components for carrying out functions relating to gas flow.
Preferably, the first supporting body also has a high-pressure purge-gas inlet valve upstream of the pressure reducing means for admitting purge-gas to the main gas flow.
In one particularly preferred arrangement, the primary module and secondary modules are arranged in a vertical stack of modules, the uppermost module having its output connecting means positioned on a side face of the supporting body.
Preferred and optional features which have been set out with regard to previous and subsequent aspects of the invention, may also be provided in accordance with this aspect of the invention.
In accordance with a fourth main aspect of the present invention, there is provided a modular gas control device for use with a container of compressed gas comprising a primary module, the primary module comprising a supporting body having a main gas flow path through the body, the supporting body having input connecting means for mounting the body on a container of compressed gas and connecting the gas flow path to communicate with the gas container, pressure reducing means for providing gas in the flow path at a selected pressure substantially lower than that in the container, a high pressure shut-off valve in the gas flow path upstream of the pressure reducing means, and filling means for filling the container with compressed gas through the input connecting means, the supporting body also having, downstream of the pressure reducing means, output connecting means for providing an outlet from the main gas flow path and for mounting on the primary module a secondary module communicating with the main gas flow path of the primary module.
It is a particularly preferred feature in this aspect of the invention that the output connecting means is positioned on an upper region, preferably an upper face, of the primary module for mounting the second module above the primary module.
In some arrangements the supporting body also has a purge-gas inlet valve upstream of the pressure reducing means for admitting purge-gas to the main gas flow.
Preferred and optional features which have been set out with regard to previous and subsequent aspects of the invention, may also be provided in accordance with this aspect of the invention.
In accordance with a fifth main aspect of the invention there is provided a modular gas control device for use with a container of compressed gas comprising a primary module, and a secondary module mounted on the primary module, the primary module comprising a supporting body having a first main gas flow path through the body, the supporting body having input connecting means for mounting the body on a container of compressed gas and connecting the gas flow path to communicate with the gas container, pressure reducing means for providing gas in the flow path at a selected pressure substantially lower than that in the container, output connecting means downstream of the pressure reducing means for providing an outlet from the main gas flow path, a high pressure shut-off valve in the gas flow path upstream of the pressure reducing means, and filling means for filling the container with compressed gas through the input connecting means, the first supporting body also having in the main gas flow path upstream of the pressure reducing means, a high-pressure safety relief device, or a high-pressure safety-relief region adapted to provide structure for mounting of a safety relief device, upstream of the pressure reducing means, a purge-gas inlet valve, or a purge-gas inlet region adapted to provide structure for a purge-gas inlet valve; and downstream of the pressure reducing means, a low pressure indicator, or a low-pressure indicator region adapted to provide structure for a pressure indicator for indicating the pressure in the fluid flow path downstream of the pressure reducing means, said secondary module comprising a second supporting body having a second main gas flow path through the body, the second supporting body having second input connecting means for mounting the body on the primary module and connecting the second main gas flow path to the output connecting means of the primary module, and second output connecting means for providing an outlet from the second main gas flow path, the supporting body of the secondary module having a combination of at least two functional components for carrying out functions relating to gas flow.
Preferred and optional features which have been set out with regard to previous and subsequent aspects of the invention, may also be provided in accordance with this aspect of the invention.
The present invention also encompasses in further aspects a gas control device, which is not necessarily for use with other modules. In such a case, there may be provided a gas control device for use with a container of compressed gas comprising: a supporting body having a main gas flow path through the body; the supporting body having: input connecting means for mounting the body on a container of compressed gas and connecting the main gas flow path to communicate with the gas container; pressure reducing means for providing gas in the flow path at a selected pressure substantially lower than that in the container; output connecting means downstream of the pressure reducing means for connecting the main gas flow path directly or indirectly to apparatus for utilizing the gas; a high pressure shut-off valve in the main gas flow path upstream of the pressure reducing means; and filling means for filling the container with compressed gas through the input connecting means; the supporting body also having, upstream of the pressure reducing means, a purge-gas inlet valve or a purge-gas inlet region adapted to provide structure for a purge-gas inlet valve.
Preferred and optional features which have been set out with regard to previous and subsequent aspects of the invention, may also be provided in accordance with this aspect of the invention.
It is to be appreciated that where features of the invention are set out herein with regard to devices according to the invention, such features may also be provided with regard to a method according to the invention, and vice versa.
In particular, and without prejudice to the generality. of the foregoing statement, there is provided in accordance with one aspect of the invention a method of supplying compressed gas comprising the steps of providing a compressed gas container having mounted thereon a primary gas control module comprising a first supporting body having a first main gas flow path through the body, the supporting body having first input connecting means for mounting the body on the compressed gas container and connecting the gas flow path to communicate with the gas container, pressure reducing means for providing gas in the flow path at a selected pressure substantially lower than that in the container, first output connecting means downstream of the pressure reducing means, and filling means for filling the container with compressed gas through the input connecting means, connecting the output connecting means to a secondary gas control module, said secondary module comprising a second supporting body having a second main gas flow path through the body, the second supporting body having second input connecting means for mounting the body on the primary module and connecting the second main gas flow path to the output connecting means of the primary module, and second output connecting means for connecting the second main gas flow path directly or indirectly to apparatus for utilizing the gas, the supporting body of the secondary module having at least two functional components for carrying out functions relating to gas flow, discharging gas from the container to the use apparatus through the gas control modules, disconnecting the use apparatus while the primary gas control module is mounted on the gas container, filling the gas container through the filling means while the primary gas control module is mounted on the gas container, and reconnecting the use apparatus while the primary gas control module is mounted on the cylinder.
In accordance with a further aspect of the present invention concerned with a method, there may be provided a method of supplying compressed gas comprising the steps of providing a compressed gas container having mounted thereon a gas control device comprising a supporting body having a gas flow path through the body, the supporting body having input connecting means for mounting the body on the compressed gas container and connecting the gas flow path to communicate with the gas container, pressure reducing means for providing gas in the flow path at a selected pressure substantially lower than that in the container, output connecting means downstream of the pressure reducing means; filling means for filling the container with compressed gas through the input connecting means, and a purge-gas inlet valve upstream of the pressure reducing means, connecting the output connecting means directly or indirectly to a use apparatus for utilizing the gas, discharging gas from the container to the use apparatus through the gas control device, disconnecting the use apparatus while the gas control device is mounted on the gas container, filling the gas container through the filling means while the gas control device is mounted on the gas container, inputting purge-gas into the main flow path through the purge-gas valve while the gas control device is mounted on the gas container, and reconnecting the use apparatus while the gas control device is mounted on the cylinder.
Reference will now be made to a sixth main aspect of the invention concerned with providing a separate filling circuit for a gas cylinder, the filling circuit being separate from the main outlet circuit from the gas cylinder. In accordance with such an aspect of the invention, there is provided a gas control device for use with a container of compressed gas comprising a supporting body having a main gas flow path through the body; the supporting body having input connecting means for mounting the body on a container of compressed gas and connecting the main gas flow path to communicate with the gas container; pressure reducing means for providing gas in the flow path at a selected pressure substantially lower than that in the container; output connecting means downstream of the pressure reducing means for connecting the main gas flow path directly or indirectly to apparatus for utilizing the gas; a high pressure shut-off valve in the main gas flow path upstream of the pressure reducing means; and filling means for filling the container with compressed gas through the input connecting means; in which the input connecting means comprises first and second flow paths and, the first flow path leading from the container to the main gas flow path through the supporting body, and the second flow path leading from the container to the said filling means, said filling means including a second high pressure shut-off valve.
Preferred and optional features which have been set out with regard to previous and subsequent aspects of the invention, may also be provided in accordance with this aspect of the invention.
In a particularly preferred form, there is provided purifying means positioned within the gas container, interposed between the first flow path and the interior of the container for purifying gas leaving the container and passing into the said main gas flow path.
Preferably the supporting body is a single body of material on or in which the functional components are mounted, and preferably the supporting body is structurally supported on the container solely by the input connecting means.
Preferably the device includes a housing surrounding the supporting body and spaced therefrom, said housing being shaped to provide means for handling the gas container, and preferably the device includes a purge-gas inlet valve upstream of the pressure reducing means for admitting purge-gas to the main gas flow path.
In some arrangements the output connecting means is positioned on an upper region, preferably an upper face, of the supporting body, and in other arrangements the output connecting means is positioned on a side region, preferably a side face, of the supporting body.
It is to be appreciated that the positioning of the output connecting means of a gas control device on either an upper face, or a side face, of the supporting body, is a consideration which affects the invention in all the aspects set out hereinbefore. In general, it is a particularly preferred feature that a module may be provided with an upwardly directed or facing output connecting means, when it is intended that a further module shall be coupled to the gas control device by way of the upwardly directed output connecting means. However, where it is intended that the module concerned shall be fitted singly to the top of a gas cylinder, with no other modules involved, or where it is intended that the module shall be the uppermost module of a series of modules secured to the top of a gas cylinder, then in such circumstances it is preferred that the output connecting means is directed or facing sideways from the module. Preferably the output connecting means faces horizontally sideways from the supporting body, although in certain circumstances the output connecting means can be directed at a angle upwardly or downwardly from a side face of the module. In yet another variation, the output connecting means may be mounted on an upper surface of the module, but may be arranged to be directed horizontally sideways at its opening when unconnected to other equipment.
However the preferred arrangement for a sole, or uppermost, module, is that the output connecting means is mounted on a side face of the module, and faces horizontally sideways from the module. Such an arrangement gives advantage in reducing the likelihood of contaminants entering the output connection means, when the output connecting means is not connected to further equipment.
In one particularly preferred independent aspect of the invention there is provided a gas control device for use with a container of compressed gas, comprising a primary module and a series of secondary modules arranged in a vertical stack of modules, the uppermost module having its output connecting means positioned on a side face of the module. Preferably the modules are constructed in accordance with any one or more of the features set out hereinbefore.
Preferred and optional features which have been set out with regard to previous and subsequent aspects of the invention, may also be provided in accordance with this aspect of the invention.
The present invention, at least in preferred embodiments thereof, provides a number of advantages over previous gas control devices and methods. Rather than just connecting a number of discrete components into a smaller control panel system, which has been proposed in some miniaturized gas control systems, the present invention encompasses redesigning and machining a group of components directly into a single body (for mechanical units), or onto an electronic chip (for example in micro-electro-mechanical system units). The invention may provide a series of modules. Each of these is independent and has distinct functions. By combining pressure regulation with other modules, the system can be extended to meet additional customer needs such as purification, vaporization, mixture generation and so on. In preferred forms all modules can give electrical output signals for indication, and receive electrical input signals for control. An integrated design can be achieved, especially with the main gas flow paths aligned along the axis of a compressed gas cylinder, to minimize leaks, eliminate dead space and redundant joints, to improve product quality and purity whilst lowering system costs.
By designing a number of different control modules for different applications, the modules can be combined to meet various customer and market needs, including the following functions:
built-in residual pressure control and safety relief
pressure module for regulating gas pressure from cylinders
flow control module
filtration and/or purifier module for control of UHP gases for electronics
venturi module for evacuation in corrosive, toxic, and pyrophoric applications
electronic control of pressure regulation for electronics
vaporizer module for converting liquefied products into gas
analyzer module to monitor gas quality
mixture module for generation of reference gas mixtures
gas blending module for processing gas mixtures
fully automated control functions for electronics
remote data acquisition, storing and control, e.g. telemeter.
The invention finds particular application in integrated circuit manufacture normally requiring the use of a gas cabinet for handling toxic, corrosive, and/or pyrophoric gases.